Re: [PATCH v8 02/14] hw/misc: Add NPCM7xx Clock Controller device model

[Philippe Mathieu-Daudé]

On 8/25/20 2:16 AM, Havard Skinnemoen via wrote:
> Enough functionality to boot the Linux kernel has been implemented. This
> includes:
> 
>   - Correct power-on reset values so the various clock rates can be
>     accurately calculated.
>   - Clock enables stick around when written.
> 
> In addition, a best effort attempt to implement SECCNT and CNTR25M was
> made even though I don't think the kernel needs them.
> 
> Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
> Reviewed-by: Joel Stanley <joel@jms.id.au>
> Reviewed-by: Cédric Le Goater <clg@kaod.org>
> Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
> ---
>  include/hw/misc/npcm7xx_clk.h |  48 ++++++
>  hw/misc/npcm7xx_clk.c         | 266 ++++++++++++++++++++++++++++++++++
>  hw/misc/meson.build           |   1 +
>  hw/misc/trace-events          |   4 +
>  4 files changed, 319 insertions(+)
>  create mode 100644 include/hw/misc/npcm7xx_clk.h
>  create mode 100644 hw/misc/npcm7xx_clk.c
> 
> diff --git a/include/hw/misc/npcm7xx_clk.h b/include/hw/misc/npcm7xx_clk.h
> new file mode 100644
> index 0000000000..cdcc9e8534
> --- /dev/null
> +++ b/include/hw/misc/npcm7xx_clk.h
> @@ -0,0 +1,48 @@
> +/*
> + * Nuvoton NPCM7xx Clock Control Registers.
> + *
> + * Copyright 2020 Google LLC
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but 
> WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> + * for more details.
> + */
> +#ifndef NPCM7XX_CLK_H
> +#define NPCM7XX_CLK_H
> +
> +#include "exec/memory.h"
> +#include "hw/sysbus.h"
> +
> +/*
> + * The reference clock frequency for the timer modules, and the SECCNT and
> + * CNTR25M registers in this module, is always 25 MHz.
> + */
> +#define NPCM7XX_TIMER_REF_HZ            (25000000)
> +
> +/*
> + * Number of registers in our device state structure. Don't change this 
> without
> + * incrementing the version_id in the vmstate.
> + */
> +#define NPCM7XX_CLK_NR_REGS             (0x70 / sizeof(uint32_t))
> +
> +typedef struct NPCM7xxCLKState {
> +    SysBusDevice parent;
> +
> +    MemoryRegion iomem;
> +
> +    uint32_t regs[NPCM7XX_CLK_NR_REGS];
> +
> +    /* Time reference for SECCNT and CNTR25M, initialized by power on reset 
> */
> +    int64_t ref_ns;
> +} NPCM7xxCLKState;
> +
> +#define TYPE_NPCM7XX_CLK "npcm7xx-clk"
> +#define NPCM7XX_CLK(obj) OBJECT_CHECK(NPCM7xxCLKState, (obj), 
> TYPE_NPCM7XX_CLK)
> +
> +#endif /* NPCM7XX_CLK_H */
> diff --git a/hw/misc/npcm7xx_clk.c b/hw/misc/npcm7xx_clk.c
> new file mode 100644
> index 0000000000..21ab4200d1
> --- /dev/null
> +++ b/hw/misc/npcm7xx_clk.c
> @@ -0,0 +1,266 @@
> +/*
> + * Nuvoton NPCM7xx Clock Control Registers.
> + *
> + * Copyright 2020 Google LLC
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful, but 
> WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
> + * for more details.
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "hw/misc/npcm7xx_clk.h"
> +#include "migration/vmstate.h"
> +#include "qemu/error-report.h"
> +#include "qemu/log.h"
> +#include "qemu/module.h"
> +#include "qemu/timer.h"
> +#include "qemu/units.h"
> +#include "trace.h"
> +
> +#define PLLCON_LOKI     BIT(31)
> +#define PLLCON_LOKS     BIT(30)
> +#define PLLCON_PWDEN    BIT(12)
> +
> +enum NPCM7xxCLKRegisters {
> +    NPCM7XX_CLK_CLKEN1,
> +    NPCM7XX_CLK_CLKSEL,
> +    NPCM7XX_CLK_CLKDIV1,
> +    NPCM7XX_CLK_PLLCON0,
> +    NPCM7XX_CLK_PLLCON1,
> +    NPCM7XX_CLK_SWRSTR,
> +    NPCM7XX_CLK_IPSRST1         = 0x20 / sizeof(uint32_t),
> +    NPCM7XX_CLK_IPSRST2,
> +    NPCM7XX_CLK_CLKEN2,
> +    NPCM7XX_CLK_CLKDIV2,
> +    NPCM7XX_CLK_CLKEN3,
> +    NPCM7XX_CLK_IPSRST3,
> +    NPCM7XX_CLK_WD0RCR,
> +    NPCM7XX_CLK_WD1RCR,
> +    NPCM7XX_CLK_WD2RCR,
> +    NPCM7XX_CLK_SWRSTC1,
> +    NPCM7XX_CLK_SWRSTC2,
> +    NPCM7XX_CLK_SWRSTC3,
> +    NPCM7XX_CLK_SWRSTC4,
> +    NPCM7XX_CLK_PLLCON2,
> +    NPCM7XX_CLK_CLKDIV3,
> +    NPCM7XX_CLK_CORSTC,
> +    NPCM7XX_CLK_PLLCONG,
> +    NPCM7XX_CLK_AHBCKFI,
> +    NPCM7XX_CLK_SECCNT,
> +    NPCM7XX_CLK_CNTR25M,
> +    NPCM7XX_CLK_REGS_END,
> +};
> +
> +/*
> + * These reset values were taken from version 0.91 of the NPCM750R data 
> sheet.
> + *
> + * All are loaded on power-up reset. CLKENx and SWRSTR should also be loaded 
> on
> + * core domain reset, but this reset type is not yet supported by QEMU.
> + */
> +static const uint32_t cold_reset_values[NPCM7XX_CLK_NR_REGS] = {
> +    [NPCM7XX_CLK_CLKEN1]        = 0xffffffff,
> +    [NPCM7XX_CLK_CLKSEL]        = 0x004aaaaa,
> +    [NPCM7XX_CLK_CLKDIV1]       = 0x5413f855,
> +    [NPCM7XX_CLK_PLLCON0]       = 0x00222101 | PLLCON_LOKI,
> +    [NPCM7XX_CLK_PLLCON1]       = 0x00202101 | PLLCON_LOKI,
> +    [NPCM7XX_CLK_IPSRST1]       = 0x00001000,
> +    [NPCM7XX_CLK_IPSRST2]       = 0x80000000,
> +    [NPCM7XX_CLK_CLKEN2]        = 0xffffffff,
> +    [NPCM7XX_CLK_CLKDIV2]       = 0xaa4f8f9f,
> +    [NPCM7XX_CLK_CLKEN3]        = 0xffffffff,
> +    [NPCM7XX_CLK_IPSRST3]       = 0x03000000,
> +    [NPCM7XX_CLK_WD0RCR]        = 0xffffffff,
> +    [NPCM7XX_CLK_WD1RCR]        = 0xffffffff,
> +    [NPCM7XX_CLK_WD2RCR]        = 0xffffffff,
> +    [NPCM7XX_CLK_SWRSTC1]       = 0x00000003,
> +    [NPCM7XX_CLK_PLLCON2]       = 0x00c02105 | PLLCON_LOKI,
> +    [NPCM7XX_CLK_CORSTC]        = 0x04000003,
> +    [NPCM7XX_CLK_PLLCONG]       = 0x01228606 | PLLCON_LOKI,
> +    [NPCM7XX_CLK_AHBCKFI]       = 0x000000c8,
> +};
> +
> +static uint64_t npcm7xx_clk_read(void *opaque, hwaddr offset, unsigned size)
> +{
> +    uint32_t reg = offset / sizeof(uint32_t);
> +    NPCM7xxCLKState *s = opaque;
> +    int64_t now_ns;
> +    uint32_t value = 0;
> +
> +    if (reg >= NPCM7XX_CLK_NR_REGS) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: offset 0x%04" HWADDR_PRIx " out of range\n",

I find "out of range" not clear, but this might be the correct
terminology.

> +                      __func__, offset);
> +        return 0;
> +    }
> +
> +    switch (reg) {
> +    case NPCM7XX_CLK_SWRSTR:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: register @ 0x%04" HWADDR_PRIx " is write-only\n",
> +                      __func__, offset);
> +        break;
> +
> +    case NPCM7XX_CLK_SECCNT:
> +        now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> +        value = (now_ns - s->ref_ns) / NANOSECONDS_PER_SECOND;
> +        break;
> +
> +    case NPCM7XX_CLK_CNTR25M:
> +        now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> +        /*
> +         * This register counts 25 MHz cycles, updating every 640 ns. It 
> rolls
> +         * over to zero every second.
> +         *
> +         * The 4 LSBs are always zero: (1e9 / 640) << 4 = 25000000.
> +         */
> +        value = (((now_ns - s->ref_ns) / 640) << 4) % NPCM7XX_TIMER_REF_HZ;
> +        break;
> +
> +    default:
> +        value = s->regs[reg];
> +        break;
> +    };
> +
> +    trace_npcm7xx_clk_read(offset, value);
> +
> +    return value;
> +}
> +
> +static void npcm7xx_clk_write(void *opaque, hwaddr offset,
> +                              uint64_t v, unsigned size)
> +{
> +    uint32_t reg = offset / sizeof(uint32_t);
> +    NPCM7xxCLKState *s = opaque;
> +    uint32_t value = v;
> +
> +    trace_npcm7xx_clk_write(offset, value);
> +
> +    if (reg >= NPCM7XX_CLK_NR_REGS) {
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: offset 0x%04" HWADDR_PRIx " out of range\n",
> +                      __func__, offset);
> +        return;
> +    }
> +
> +    switch (reg) {
> +    case NPCM7XX_CLK_SWRSTR:
> +        qemu_log_mask(LOG_UNIMP, "%s: SW reset not implemented: 0x%02x\n",
> +                      __func__, value);

Isn't this sufficient?

           qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);

> +        value = 0;
> +        break;
> +
> +    case NPCM7XX_CLK_PLLCON0:
> +    case NPCM7XX_CLK_PLLCON1:
> +    case NPCM7XX_CLK_PLLCON2:
> +    case NPCM7XX_CLK_PLLCONG:
> +        if (value & PLLCON_PWDEN) {
> +            /* Power down -- clear lock and indicate loss of lock */
> +            value &= ~PLLCON_LOKI;
> +            value |= PLLCON_LOKS;
> +        } else {
> +            /* Normal mode -- assume always locked */
> +            value |= PLLCON_LOKI;
> +            /* Keep LOKS unchanged unless cleared by writing 1 */
> +            if (value & PLLCON_LOKS) {
> +                value &= ~PLLCON_LOKS;
> +            } else {
> +                value |= (value & PLLCON_LOKS);
> +            }
> +        }
> +        break;
> +
> +    case NPCM7XX_CLK_CNTR25M:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "%s: register @ 0x%04" HWADDR_PRIx " is read-only\n",
> +                      __func__, offset);
> +        return;
> +    }
> +
> +    s->regs[reg] = value;
> +}
> +
> +static const struct MemoryRegionOps npcm7xx_clk_ops = {
> +    .read       = npcm7xx_clk_read,
> +    .write      = npcm7xx_clk_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .valid      = {
> +        .min_access_size        = 4,
> +        .max_access_size        = 4,
> +        .unaligned              = false,
> +    },
> +};
> +
> +static void npcm7xx_clk_enter_reset(Object *obj, ResetType type)
> +{
> +    NPCM7xxCLKState *s = NPCM7XX_CLK(obj);
> +
> +    QEMU_BUILD_BUG_ON(sizeof(s->regs) != sizeof(cold_reset_values));
> +
> +    switch (type) {
> +    case RESET_TYPE_COLD:
> +        memcpy(s->regs, cold_reset_values, sizeof(cold_reset_values));
> +        s->ref_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> +        return;
> +    }
> +
> +    /*
> +     * A small number of registers need to be reset on a core domain reset,
> +     * but no such reset type exists yet.
> +     */
> +    qemu_log_mask(LOG_UNIMP, "%s: reset type %d not implemented.",
> +                  __func__, type);

Clean :)

> +}
> +
> +static void npcm7xx_clk_init(Object *obj)
> +{
> +    NPCM7xxCLKState *s = NPCM7XX_CLK(obj);
> +
> +    memory_region_init_io(&s->iomem, obj, &npcm7xx_clk_ops, s,
> +                          TYPE_NPCM7XX_CLK, 4 * KiB);
> +    sysbus_init_mmio(&s->parent, &s->iomem);
> +}
> +
> +static const VMStateDescription vmstate_npcm7xx_clk = {
> +    .name = "npcm7xx-clk",
> +    .version_id = 0,
> +    .minimum_version_id = 0,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT32_ARRAY(regs, NPCM7xxCLKState, NPCM7XX_CLK_NR_REGS),

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> +        VMSTATE_INT64(ref_ns, NPCM7xxCLKState),
> +        VMSTATE_END_OF_LIST(),
> +    },
> +};
> +
> +static void npcm7xx_clk_class_init(ObjectClass *klass, void *data)
> +{
> +    ResettableClass *rc = RESETTABLE_CLASS(klass);
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    QEMU_BUILD_BUG_ON(NPCM7XX_CLK_REGS_END > NPCM7XX_CLK_NR_REGS);
> +
> +    dc->desc = "NPCM7xx Clock Control Registers";
> +    dc->vmsd = &vmstate_npcm7xx_clk;
> +    rc->phases.enter = npcm7xx_clk_enter_reset;
> +}
> +
> +static const TypeInfo npcm7xx_clk_info = {
> +    .name               = TYPE_NPCM7XX_CLK,
> +    .parent             = TYPE_SYS_BUS_DEVICE,
> +    .instance_size      = sizeof(NPCM7xxCLKState),
> +    .instance_init      = npcm7xx_clk_init,
> +    .class_init         = npcm7xx_clk_class_init,
> +};
> +
> +static void npcm7xx_clk_register_type(void)
> +{
> +    type_register_static(&npcm7xx_clk_info);
> +}
> +type_init(npcm7xx_clk_register_type);
> diff --git a/hw/misc/meson.build b/hw/misc/meson.build
> index 99ffb9f9e8..531cc31dcc 100644
> --- a/hw/misc/meson.build
> +++ b/hw/misc/meson.build
> @@ -51,6 +51,7 @@ softmmu_ss.add(when: 'CONFIG_IMX', if_true: files(
>  softmmu_ss.add(when: 'CONFIG_MILKYMIST', if_true: files('milkymist-hpdmc.c', 
> 'milkymist-pfpu.c'))
>  softmmu_ss.add(when: 'CONFIG_MAINSTONE', if_true: files('mst_fpga.c'))
>  softmmu_ss.add(when: 'CONFIG_NPCM7XX', if_true: files(
> +  'npcm7xx_clk.c',
>    'npcm7xx_gcr.c',
>  ))
>  softmmu_ss.add(when: 'CONFIG_OMAP', if_true: files(
> diff --git a/hw/misc/trace-events b/hw/misc/trace-events
> index dbf90db8ed..a010699b4f 100644
> --- a/hw/misc/trace-events
> +++ b/hw/misc/trace-events
> @@ -111,6 +111,10 @@ mos6522_set_sr_int(void) "set sr_int"
>  mos6522_write(uint64_t addr, uint64_t val) "reg=0x%"PRIx64 " val=0x%"PRIx64
>  mos6522_read(uint64_t addr, unsigned val) "reg=0x%"PRIx64 " val=0x%x"
>  
> +# npcm7xx_clk.c
> +npcm7xx_clk_read(uint64_t offset, uint32_t value) " offset: 0x%04" PRIx64 " 
> value: 0x%08" PRIx32
> +npcm7xx_clk_write(uint64_t offset, uint32_t value) "offset: 0x%04" PRIx64 " 
> value: 0x%08" PRIx32
> +
>  # npcm7xx_gcr.c
>  npcm7xx_gcr_read(uint64_t offset, uint32_t value) " offset: 0x%04" PRIx64 " 
> value: 0x%08" PRIx32
>  npcm7xx_gcr_write(uint64_t offset, uint32_t value) "offset: 0x%04" PRIx64 " 
> value: 0x%08" PRIx32
>